Of racism and discontent; A Man's Life, by Roger Wilkins.New York: Simon & Schuster. 371 pp. $17.95

Few qualities are more sorely needed in the field of race relations than honesty. Few qualities are more elusive. I'm speaking, here, of the kind of honesty that enables us not only to recognize how racism has shaped our perceptions, but to free ourselves from this distorting influence.

In his autobiography, Roger Wilkins has sought to portray the nature and impact of racism in America. His book has much to teach us, but it is laced with contradictions, and its message is obscured by a haze of bitterness and self-pity.

His subject matter is, by its very nature, explosive, and his responsibility to strive for fairness and balance - even within the framework of an autobiography - was compounded by the positions of high trust and influence he has held.

Mr. Wilkins was assistant attorney general of the United States in the Johnson administration, held a top position in the Ford Foundation, and was on the editorial boards of both the Washington Post and the New York Times. His work was included in the Post's Watergate package, which won the Pulitzer Prize. And, before his resignation from the Times, Wilkins was awarded a regular, bylined news analysis column.

But Mr. Wilkins often seems to have used the book more for catharsis than for communication. Taken as a whole, it's a misuse of history, social analysis, and the racial agonies of a nation to justify a more private unhappiness.

The most effective sections deal with Wilkins's childhood, youth, and college years, vividly portraying the humiliations even the most privileged blacks confront when growing up in America. Wilkins - who was the nephew of the NAACP's Roy Wilkins, and who was related by blood or friendship to many of the nation's most prominent blacks - was exposed to an extraordinary collection of role models. He was spared material deprivation. Yet his book shows what it is like to be torn between two cultures, and to come of age without a clear sense of identity.

Had he steered clear of vindictiveness and a self-serving interpretation of events - which surfaced once he began to write of his adult years - Wilkins's book could have been outstanding.

But he has used his book, instead, largely as a means of settling old scores. He judges himself by his aspirations and accomplishments (attributing his shortcomings to the pressures under which he labored) while judging others by their worst moments, which he recounts with an often repugnant satisfaction.

And although he defines racism as ''the evasion of individual responsibility by finding scapegoats for disappointment, failure, and bad behavior,'' Wilkins does not recognize himself in this description.

He writes, for example, that ''in my explorings I caught some diseases . . . depression, divorce, and what people used to call in a genteel fashion, a drinking problem.''

And he goes beyond analyzing problems to construct an elaborate justification for hopelessness and despair.

In writing a personal and social history, credibility is everything. To win our trust, Wilkins needed to conform his social analysis to a coherent world view, and to demonstrate that his intentions in writing about others were honorable.

These are the very things he has failed to do. Those who shunned Wilkins or failed to give him what he thought was his due are presented as bigots. Those who rewarded his achievements, or showered him with love and concern, are also condemned - albeit more gently - for corrupt motives and for inner blindness. We're never told what course of action would have been acceptable.

One wonders what heights he might reach if he were to choose to set all bitterness aside, to view his talents not as personal possessions to be withheld from an unworthy world nor as weapons with which to wound his opponents, but as gifts to be used in the spirit of service, over the long haul.

''A Man's Life'' has received widespread publicity, and was excerpted, at length, in Harper's magazine. It is to be hoped that all those who read this book will value Mr. Wilkins's insights and achievements without adopting his despairing pessimism.